目的 研究不同强度的力学载荷对破骨细胞及其前体细胞增殖、分化和功能的影响。方法 以破骨诱导液培养RAW264.7破骨前体细胞，同时施加3 d的周期性张应变，然后培养4 d；另外一组RAW264.7细胞以破骨诱导液培养4 d，将其诱导为破骨细胞，再施加3 d的周期性张应变。结果 在不同张应变下，两组细胞增殖活性的变化大致相同，但细胞抗酒石酸酸性磷酸酶（tartrate-resistant acid phosphatage, TRAP）活性和破骨细胞（TRAP阳性多核细胞）数量的变化明显不同。在2 500 με的中等强度张应变下，第1组的TRAP活性降幅和破骨细胞数量减幅均最高，而后者TRAP活性降幅和破骨细胞数量减幅均最低。 结论 不同张应变对分化初期破骨前体细胞和已分化出破骨细胞的破骨前体细胞的破骨分化和功能状态的影响有明显差异。
Objective To investigate the effect of mechanical loading with different magnitudes on the proliferation, differentiation and activity of preosteoclasts and osteoclasts. Methods One group of RAW264.7 preosteoclastic cells cultured in osteoclast inductive medium were subjected to the cyclic tensile strain for three days, and then cultured for four days; the other group of RAW264.7 cells were induced in osteoclast inductive medium for four days to be osteoclasts, then subjected to the cyclic tensile strain for three days. Results Under the tensile strain at different magnitudes, the proliferation variations in two groups of RAW264.7 cells were approximately identical, but changes in the activities of tartrate-resistant acid phosphatage (TRAP) and numbers of TRAP-positive multinucleated cells (osteoclasts) in the two groups were significantly different. Under the moderate tensile strain (2 500 με), the reduction of TRAP activity and osteoclasts number were both the highest in the first group, and both the lowest in the second group. Conclusions The influence of different tensile strain on osteoclast differentiation and osteoclastic activity of preosteoclasts in early differentiation is different to that of the preosteoclasts already differentiated into osteoclasts.